Lubricants are substances that reduce friction and heat dissipation between operating machine parts. The purpose of the paper is to investigate the possibility of improving the tribological properties of biodegradable vegetable oils. The objects of the research were lubricating oils produced based on selected plant oils (rapeseed, sunflower, corn, soybean) and Priolube ester oil containing nanoparticle hexagonal boron nitride (h-BN) and a dispersant. The research assesses the physicochemical properties, the wear load limit, the welding load, and the friction coefficient of the prepared oil compositions. The article compares the results with those obtained during the CB30 engine and PAO4 oil tests. The test results confirm that lubricating oils prepared in this way are characterized by promising tribological properties, are easy to prepare, and are environmentally friendly. The appropriate method of preparation has a significant impact on the quality of the obtained oils.